Storing people

If you really want a cheap, safe place for people to stay temporarily (or permanently, for that matter), upsize a standard storage building, one of those places where you can rent a room with a sliding metal garage-style door usually accessible from the outside in which to stash your stuff, with more substantial doors, plumbing, and so on. The building could be cinderblock with substantial metal doors which would be quite secure, with skylights in the roofs of substantial acrylic material to resist break-in. The result would be a cheap way for people to live in reasonable security and fairly high density.